Process of mercerizing



' Patented May 13, 1936 UNI- ED STATES fPArENr orifice" HARR IP nAssn'r'r, or 'GYNTHIANA, KENTUCKY, ANn 'inoMAs F. BANIGAN, or CLIFTON HEIGHTS, PENNSYLV NIA, ASSIGNORS, BY MESNE ASSIGNMENTS, To mes, ZBASSETT & SLAUGHTER, me, or PHILADELPHIA, PENNSYLVANIA, A, con- POBATION OF PENNSYLVANIA rnocnss or ERcnRI'zING No Drawing.

This invention relates toproces'ses. ofmercerizing and particularly mercerizing woven and unwoven, natural cellulose fibres such as cotton andlinen having interwoven therewith artificial filaments commonly known asartificial silk, although our invention is adapted for advantageous use in mercerizing natural cellulose fibres unassociated with artificial silk filaments. v s

Heretofore it has been proposed to protect artificial silk filaments of viscose silk interwoven with natural cellulose fibres from the deleterious action of the mercerizing solut'ionby the addition to such solution of so-called caustic alkali modifying agents intended to prevent such deleterious action, but such processes have so far as we have been able to learn, not come into commercial use and, from our experiments, they appear to be incapable'of successful practical use. In the operation of our process, we recognize two individual types of artificial silk; first, silk consisting essentially of pure cellulose including viscose, and second, cellulose ester-silks consisting of cellulose in combina tion'with organic acids. The term cellulose containing materials as herein'employed includes both of these types of artificial silk as well as natural cellulose fibres.

We have discovered that artificial fila-' ments of cellulose silk or artificial filaments of cellulose esters intermingled or interwovenwith natural cellulose fibres cannot be protected from deleterious action 'of-caustic alkali mercerizing solution in the mercerizing process -by the mere use in the merceriza ing bath of a so-called caustic alkali modifying agent capable- 0f repressing the tend- L ency ofthe caustic alkali to decompose the 40 artificial silk in the mercerizing solution and thereby injure the quality of the artificial cellulose filaments or cellulose ester filaments during the mercerizing process Protection in-the initial step of mercerizing can'be ob- ,tained by introducing the intermingled or interwoven fibres or filaments free of water or,of water of "weak solutions into the mercerizing solution containing, in additionto the caustic alkali, an agent capable of substantially repressing the tendency of a the Application filed January 30, 1925. Serial Nb, 5,887.

caustic-alkali to ioni ze and consequently the tendency of the artificial cellulose or the cellulose ester to decompose in the mercerizing solution. v

' By the expression free of water as used herein, we refer to water as such, that is, containing no substantially free and uncombined water, as distinguished from af solution of a salt wherein the solution is substantially saturated with asalt and accordingly incapable of performing or acting as water or weak solutions of salts in the practice of our process.

We have also discovered that cellulose esters whenever exposed to the action of caustic alkali solution of sufficient concentration to effect any mcrcerization of cellulose areinjured and their qualityjmpaired unless such caustic alkali solution is modified by the presence of a protective material capable of counteracting or repressing the tendency of the caustic alkali to ionize in solution and consequently capable of repressing the tendency of the cellulose ester to decompose when in contact with such caustic alkali solution under the conditions ordinarily employed in the process of mercerization.

We have found that when the caustic alkali sollition containing the modifying agent is washed from the material being treated with water the ionization resulting from the reduction of the concentration "of solution of salts remaining in the fibres materially in--.

jures the artificial silk filaments and causes themrto assume a ropey or .gelatinous'consistency and when under tension deprives [them of lust-re as well as weakening their strength. Thus the use of sodium acetate and similar. salts as a modifying agent only in the mercerizin'g bathbecomes practically ineffective and renders the process inoperative unless the artificial silk fibres are protectecl during-the washing operation. We therefore proceed as follows; After the mercerizfng treatment is completed the process is continued by washing the mercerizing solution fromthe treated fibres by using a substantially saturated solution of the agent employed tojrepress the tendency of the caustic, alkali "to ionize and the artificial silk to dei 40 We have found 'that'sodium acetate is prefcompose, until the concentration of the caustic alkali solution leftin the fibres has been reduced below the concentration at which mera cerization of the cellulose or decomposition of theartificial silk can occur.

Thereafter the material is washed'substantially free of the solution of suchagent and finally bleaching, dyeing or finishing the texv maybe carried out in any suitable man ner. We also have discovered that artificial cellulosefilaments and natural cellulose fibres a e injuriously afi'ectedwhenever they are exp sed'to'the action of strong caustic alkali" solution unless the-alkali solution is suitably modified to repress the ionization of the caustic alkali. Greater lustre and softness are 7 .obtained when the fibres and filaments are protected against-the harmful efiect of ionization of the caustic alkali solutionat all stages,

of the mercerizing process when the fibres and filaments'are'in contact with alkali solu-.

tion having suflicient concentration, to produce mercerization of cellulose as well as when the fibres and filaments are protected against the action of the caustic alkali only to the extent of modifying the mercerizing solution itself. 1

.The natural cellulosefibres, cellulose ester filaments, artificial cellulose filament'smr mixtures of the same, may-be introduced dry into the mixed mercerizing bath but we prefer to wet the fibres and filaments before introducing them into the mercerizing solution with 1 a substantially concentrated solution of the agent employed to repress thedecomposition of the artificial cellulose material and the ionization of the caustic alkali in the merceri'zin'g bath. 'Q

, erably and usually superior to all other agents fQLI'GPI'GSSlHg the decomposition of thecelv;

lu' lcse estersin' the mercerizing'bath, whichwe have investigated and we prefer-to make 7 use of this salt in the practice of our process.

We have also discoveredithat not only are filaments of'cellulose -esters and artificial cellulose filaments inj-uriously affected by the action of causticalkali in mercerization with an unmodified mercerizingsolution, but'that natural cellulose fib-resand particularly woven cotton fibres have/a-stilf'and harsh feeling after merceriz ation by the ordinary method of mercerization, their flexibility and softness having been impaired; We have discovered also that this injurious effect of themerceri'zing solution is prevented by the use of sodium acetate as described in connection With the treatment of-intermingled and interwoven Q natural cellulose fibres, cellulose ester filaments,- and, artificial cellulose filaments;

In the preferred practicebf our process,

the natural cellulose fibres or such fibres intermingled or interwoven with artificial'cellulose filaments or cellulose ester filaments, or

vcaustic alkali.

filamejhts,'which comprises introducing said mixtures of the-same, either loose, in thread a or in yarn, or'woven into fabric, are first moistened 'and preferably thoroughly wet with a substantially saturated solution of sodium acetate,then' subjected to the well known mercerizing process in a bath con-,

taining in addition tofthe caustic alkali, sodium acetate in substantially saturated solu-' tion therein. The-treated material. is then washed substantially. free of caustic alkali with a substantially concentrated solution ofsodium acetate and such material washed substantially free of sodium acetate solution with water. The-Washed material is finally dyed, bleached, or finished in'any' suitable manner.

' If some agent other than sodium acetate such as heretofore has been suggested for Having described our invention, we claim: 1. Theprocess of treating cellulose textiles and the-like, containing artificial silk material into acaustic alkali mercerizing solution containinga. salt which has an organic base andwill not by reaction of th ca istic alkali therewith undergo change in its chemical COIIlpOSltlOIl, 'I'm0V1Ilg'Sa1d material from said'Inercerizingsolution and then washing with a solution of said salt until the concentration of the'caustic alkali has been reduced below that at which mercerization takes place.

2. The process of treating cellulose tex-' tiles andthe. like, containing artificial silk filaments, which comprises introducing said material into a caustic alkali mercerizing solution containing sodium acetate,'m erceriz-.

ing the natural cellulose fibres therein, re- 115 moving said material fro'msaid mercerizing solution and then washing with sodium acetat until the concentration of the caustic alkali in'the fibres andfilaments has been reducedbelow that takes. place. s; 1 l

3. The process of treating cellulose texi tiles and the like, containing artificial silk filaments, which comprises introducing said material intoa caustic-alkali mercerizing soat which mercerizationj lution, containing a salt which has an organic hase and will not byreaction of the caustic alkali'therewith undergo change in its chemical composition, removing said material from said mercerizing solution, washing with 'a 130 solution of said salt until the concentration of the caustic alkali has been reduced below that at which mercerization takes place, and then washing with water until substantially free from said last named salt.

4. The process of treating cellulose textiles and the like, containing artificial silk filaments, which comprises introducing said material into a caustic alkali mercerizing solution, containing sodium acetate, mercerizing the natural cellulose fibres therein, removing said material from said mercerizing solution, washing with sodium acetate until the concentration of the caustic alkali in the fibres and filaments has been reduced below that at which mercerization takes place, and

then washing with water until substantially free from said last named sodium acetate.

5. A process of mercerizing textiles and the like whichinclude natural cellulose fibres that may have intermingled or interwoven therewith artificial cellulose filaments,. or mixtures of the s ame, the steps comprising, first wetting the material with a substantially saturated solution of sodium acetate, then introducing the thus treated material into a mercerizing bath containing in addition to caustic alkali, sodium acetate in substantially saturated solution therein, subjecting the material to the mercerizing .processtherein, washing the treated material substantially free of caustic alkali wit-h a substantially saturated solution of sodium acetate, and washing such material substantially free of sodium acetate solution.

6. A process of mercerizing textiles and the like which. include natural cellulose fibres that may have intermingled or interwoven therewith artificial cellulose filaments, cellulose ester filaments, or mixtures of the'same,

the steps, comprising, introducing the material into a mercerizing bath containing in addition to caustic alkali, sodium acetate in like which include natural cellulose fibres substantially saturated solution therein, washing the treated material substantially free of caustic alkali with a substantially sat urated solution' of sodium acetate, and washing such material substantially free of sodium acetate solution.

7. A'process of mercerizing textiles and the that may have intermingled or interwoven therewith artificial cellulose filaments, cellulose ester filaments, or mixtures of the same, the 'steps, comprising, first wetting the material with a substantially saturated solution of an agent for protecting cellulosic fibres and filaments from the injurious action of caustic soda,such agent being a material capable of repressing the ionization of caustic alkali and of repressing the decomposition of cellulose ester filaments in contact with the caustic alkali mercerizing solution, subjecting the thus treated material to the mercerizing process in a bath containing in addition to' stantially freeof caustic alkali with a substantially saturated solution of such ionization repressing agent, and washing the material substantially free of the solution of such agent.

8. A process of mercerizing textiles and the like which include natural cellulose fibres that may have intermingled or interwoven therewith artificial cellulose filaments, cellulose ester filaments, or mixtures of the same, the steps, comprising, introducing the material into a mercerizing bath containing in addition to the caustic alkali an agent for repressing the ionization of caustic alkali and repressing the decomposition of cellulose ester filaments in contact with the caustic alkali mercerizing solution, subjecting the material to the mercerizing process in such bath, washing the treated material substantially free of caustic alkali with a substantially saturated solution of such ionization repressing agent, and washing the material substantially free of the solution of such agent.

9. In the process of mercerizing natural cellulose fibres having intermingled or interments from said mercerizing solution, and

then washing with a solution of said salt until the concentration of the caustic alkali has been reduced below that at which mercerization takes place.

10. In the process of mercerizing natural cellulose fibres having intermingled or interwoven therewith cellulose acetate filaments, the step of subjecting such fibers and filaments substantially free of water to the mercerizing action of a caustic alkali mercerizing solution containing sodium acetate in substantially saturated solution therein. 7 a 11. In the process of mercerizing substantially water-free intermingled or interwoven natural cellulose fibers and cellulose acetate by -the action of a caustic alkali mercerizing solution, protecting the cellulose acetate filaments from the injurious action of the caustic alkali therein during the mercerizing process by the action of sodium acetate in ,thefein by the action of an acetate freely $0111 ble in the' mercerizing solution and in substantially saturated solution in such mercerizing solution.

In testimony whereof we aflix our signatures. v,

' HARRY P. BASSETT.

THOMAS F. BANIGAN. 

